Results: Under enhanced MSCT, 50 vasculitic lesions were identified and were divided into five types (A–E) according to the CT findings on the basis of luminal changes. There were more vasculitic lesions observed below (n=30) the diaphragm than above it (n=20). Aneurysms and aneurysmal dilatation were more likely to be found in the aortaventralis (n=5), aortic arch (n=3) and iliac arteries (n=3). Most of the vascular lesions were characterized by wall thickening with a normal lumen (n=15) and slight stenosis (n=22). The affected vascular walls all thickened to between 4 and 18 mm. The walls of 19 patients (90.4%) were well circumscribed. The wall thickness of the aorta, including the aortaventralis and aortic arch, was more notable than at the other vascular sites. Fourteen patients were followed-up for 2-24 months. Wall thickness decreased in all cases. The average maximum thickness before- and after- therapy were 12.2±2.7mm, 6.1±1.8mm, which were significantly different (P<0.001). The lumens of two patients were found to be slightly enlarged, while those of the other cases were unchanged after therapy.

Conclusion: IgG4-RD vascular lesions can be divided into five types, which are more likely to be present in the aorta and its main branches and can rapidly diminish after steroid therapy. The lumen may be unchanged or slightly enlarged.